Parkinsonian symptoms can cause substantial morbidity, including falls and fractures, decline in capacity for self-care, and premature institutionalization. Little is known about the frequency with which drug- induced parkinsonian symptoms (DIPS) occur following use of neuroleptic (anti-psychotic) medication. This problem is of concern because of age- related decrease in dopaminergic function, the heavy use of neuroleptics in the elderly, and the potential confusion of DIPS with idiopathic Parkinson's disease, leading to erroneous diagnosis and treatment with an additional medication. DIPS represents one of the more frequent and potentially disabling adverse drug effects in aging which could be targeted for educational intervention if more were known about its prevalence and associated risk factors. The proposed project is an epidemiologic study making use of a database developed by the study team that contains all reimbursed health care encounters for the entire Medicaid population of New Jersey from 1980 to 1988, supplemented by the complete claims histories of all participants in the state's Pharmacy Assistance for the Aged and Disabled (PAAD) program, and the claims file for Medicare (Parts A and B) for New Jersey for the same period. A case-control design will identify all new recipients of medications commonly used to treat parkinsonian symptoms, as well as all recipients diagnosed as having parkinsonian symptoms. Controls will be drawn from the same population of Medicaid recipients. The relative frequency of prior use of specific neuroleptic agents will be measured among cases and controls, as will the frequency of use of two related drugs, metoclopramide and prochlorperazine. The study will generate odds ratios that will identify the increase in risk of developing parkinsonian symptoms in patients given specific neuroleptic medications relative to patients who do not receive these agents. All analyses will be stratified by age, gender, residence in nursing homes, and by numbers of Medicaid prescription claims during Medicaid eligibility. Differences in risk among the various commonly used neuroleptics will be defined as well as the role of age, dose, and duration of use as effect modifiers. Health services research questions will also be studied, including characterization of prescribers and health-care settings with high rates of DIPS.